Abstract: A method for detection of trace transgenic rice materials was built by using semi-nested PCR. According to SPS,Cry1A(b)/Cry1A(c) and Btc genes in transgenic rice Bt63,six pairs of primers were designed for general PCR and semi-nested PCR. Results of amplification showed that detection sensitivity of general PCR and semi-nested PCR in accordance with DNA concentration are 1 ng/μl and 10-3 to 10-4 ng/μl,respectively. The latter is 103 to 104 times of the former. In the aspect of mass percentage,the detection sensitivity of general PCR is 0.1% to 1% and semi-nested PCR is 0.001% to 0.01%,the latter being at least 10 times of the former. In the transgenic detection of food samples,the DNA band of SPS gene could not be obtained or confused by general PCR from frozen rice dumpling,rice cereal and cheese pancake samples. Further amplification with semi-nested PCR,a distinct and unique DNA band of SPS gene could be observed from these samples. The other two genes,Cry1A(b)/Cry1A(c) and Btc are not obtained with general PCR and semi-nested PCR from all the food samples.

Key words:  , trace transgenic rice； semi-nested PCR； detection；